var t = null;

t = setTimeout(time, 1000); //开始执行

function time()

{

    clearTimeout(t); //清除定时器

    dt = new Date();

    var y = dt.getYear() + 1900;

    var mm = dt.getMonth() + 1;

    var d = dt.getDate();

    var weekday = ["星期日", "星期一", "星期二", "星期三", "星期四", "星期五", "星期六"];

    var day = dt.getDay();

    var h = dt.getHours();

    var m = dt.getMinutes();

    var s = dt.getSeconds();

    if (h < 10) { h = "0" + h; }

    if (m < 10) { m = "0" + m; }

    if (s < 10) { s = "0" + s; }

    document.getElementById("timeShow").innerHTML = y + "年" + mm + "月" + d + "日 " + weekday[day] + " " + h + " : " + m + " : " + s + " ";

    t = setTimeout(time, 1000); //设定定时器，循环执行           

}